A psychiatric epidemiologic study of the adult population in the Island of Puerto Rico is proposed. The study will be conducted utilizing the Master Sample Survey of the Health Department of Puerto Rico. The spanish version of the NIMH-Diagnostic Interview Schedule (DIS) will be used to estimate the prevalence of the following ten psychiatric disorders: organic brain syndrome, major depression, dysthymia, bipolar disorder, obsessive compulsive disorders, schizophrenic disorders, panic disorders, phobias, somatization disorders, alcohol abuse and alcohol dependence. The validation and adaptation of the Spanish version of the DIS for the Puerto Rican population, prior to its epidemiologic application, is also proposed.